Atypical Nevus

What is an atypical nevus?

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An atypical nevus is an abnormal mole on the skin. Moles form when melanocytes – pigmented cells – group together. These growths are extremely common. A typical adult will have between 10 and 40 moles at any given time scattered all over the body. Most are typical and benign, but atypical nevi are also common. These moles, while less frequent, occur in around 10 percent of Americans.

Atypical nevi can be benign, or they can be cancerous. If you find an atypical nevus on your body, schedule an appointment with your dermatologist as soon as possible. While many of these moles are harmless, some are not. An atypical nevus could just be a strange-looking mole, but it could also be skin cancer. Developing a relationship with a trusted dermatologist, as well as receiving regular skin checks, can help address atypical nevi faster and more effectively.

What causes an atypical nevus?

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Atypical nevi, also called dysplastic moles, form when pigmented cells cluster together. In some cases, their formation is spontaneous and caused by sun damage. In other cases, it is genetic.

Atypical nevi can indicate skin cancer. Atypical moles are considered to be pre-cancerous. This means they are more likely to turn into melanoma than regular moles. However, not every person with an atypical nevus will develop skin cancer.

Some people are at a greater risk for developing an atypical nevus. This includes:

  • People with many freckles
  • People with fair skin
  • People with light eyes and/or hair
  • People with many moles
  • People who have a family history of skin cancer
  • Those who have experienced regular sunburns throughout their lives
  • People who tan or get sunburns easily

If you are at a greater risk for developing atypical nevi, it is important to receive regular skin checks from a dermatologist or primary care physician. While an atypical nevus does not necessarily lead to cancer, it can. Catching abnormal moles early is key to quick and efficient treatment.

What are symptoms of an atypical nevus?

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Atypical nevi can take many forms. It is important to learn how to distinguish between regular and abnormal moles. For reference, a typical mole will be one color (brown, red, blue, clear, or tan), even on all sides, have a well-defined border, and measure less than 5 millimeters across. Additionally, typical nevi do not change over time.

An atypical nevus is different. These moles can be raised or flat. They will have one or more of the following characteristics:

  • The mole is larger than 5 millimeters across.
  • The mole has an irregular and uneven shape.
  • The mole has a faded border.
  • The skin surface is rough or scaly.
  • The mole has more than one color, like black, tan, pink, brown, white, and/or clear.

Atypical nevi can appear anywhere on the body. They are more likely to form on parts of the body that experience regular sun exposure. This includes the scalp, torso, head, neck, and upper arms. According to the American Academy of Dermatology, atypical nevi rarely form on the face.

What are potential complications from an atypical nevus?

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Atypical nevi are often harmless. However, they are considered precancerous. This means they are more likely than a typical nevus to turn into a skin cancer, like melanoma. This is the most serious atypical nevus complication and can require extensive treatment. Atypical nevi may also indicate basal cell carcinoma or squamous cell carcinoma. People with 5 or more atypical nevi have a significantly higher risk of developing melanoma.

Because atypical nevi can turn into skin cancer, it is important to see a doctor as soon as you observe the growth. Take a photo of the mole and schedule an appointment with your dermatologist or primary care physician.

When to see a doctor for an atypical nevus?

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If you discover an atypical nevus, make an appointment with a healthcare professional as soon as possible. While most abnormal moles are not skin cancer, many are. Receiving swift medical attention can significantly improve treatment viability and prognoses.

Doing regular self-examinations can help alert a doctor to a new or changing nevi. To do a self-examination, take a few minutes every month to scan the body for new or changing growths. For harder-to-see places, use a mirror or a partner. Remember to check your palms, the soles of your feet, the back of your neck, your scalp, the backs of your arms, and behind your ears. If you notice any new or different moles, take a photo for reference. This can help you and your doctor understand how – if at all – the mole is changing.

If it important that patients do not remove atypical nevi at home. Certain over-the-counter treatments, like skin tag removers and wart freezes, can cut off the mole. However, if the nevus happens to be cancerous, the cancer may not be contained to the growth. In some cases, the cancer may have spread. Seeing a doctor and receiving a biopsy is the only way to ensure that a growth is benign. Removing the mole yourself may make diagnosis more difficult.

How is an atypical nevus diagnosed?

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When seeing a doctor for an atypical nevus, they will conduct a visual examination. If you have an atypical nevus, the doctor will measure and photograph the growth. If the mole has changed, the doctor may elect to remove and/or biopsy it.

Mole removal takes just a few minutes and is typically done during the appointment. Once the mole is biopsied or fully removed, the doctor will send it to a lab for examination. Results of this lab analysis will determine the diagnosis. In most cases, diagnoses will take around one week to complete.

Mole removal or biopsy may take one of several forms. Common biopsy procedures include:

  • Excisional biopsy: The dermatologist or physician will use a scalpel to remove the atypical nevus. They will also remove a small portion of the healthy skin around the growth. This type of biopsy may require a stitch to close. It may result in a small scar.
  • Shave biopsy: During this biopsy procedure, the physician will shave thin layers of the skin with a scalpel or razor. This type of biopsy does not typically require stitches, but it may cause bleeding.
  • Punch biopsy: A punch biopsy requires the use of a specialized tool. The doctor will use a small, circular blade to cut, or “punch” out, a deeper section of the affected tissue. This biopsy may require stitches and cause a small scar.

If your atypical nevus is biopsied, the doctor will send you home with care instructions for the wound site. Clean the site and keep it out of direct sunlight. This will help to prevent scarring.

What are common treatments for atypical nevi?

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In most cases, removal is the treatment for an atypical nevus. If the mole is biopsied or removed and found to be benign, no further treatment is necessary. However, if the nevus is cancerous, the doctor will recommend additional treatment.

If the atypical nevus is an early-stage basal cell carcinoma, squamous cell carcinoma, or melanoma, removing the mole may have been enough to treat the cancer. The doctor will typically elect to take a larger skin sample to ensure that all of the cancer has been removed. However, if the cancer has spread, systemic treatment may be necessary. This could include radiation therapy and/or chemotherapy.

Removing an atypical nevus does not prevent additional moles from forming. Even after mole removal, it is important to continue conducting routine skin checks. If you discover another atypical nevus, schedule another appointment with your doctor.

What is the outlook for people with an atypical nevus?

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In most cases, people with atypical nevi live long, healthy, and normal lives. Most atypical nevi, though considered to be precancerous, do not turn into cancer. Often, removal is quick and effective treatment, and the patient can continue life as normal.

Cancerous atypical nevi patients can also live normal lives. If an abnormal mole is caught and treated early, the skin cancer does not have a chance to spread. In these cases, the patients become cancer free very quickly, and they can continue with their lives. But, if the cancer causing the atypical nevus has spread, additional treatment may be necessary.

Remember that metastasis, or spread, is rare with most skin cancers. Basal cell carcinoma has a 0.0028 to 0.55% chance of spreading. Similarly, only around 1.4% of squamous cell carcinomas will spread beyond the atypical nevi. And, while melanoma is the most likely skin cancer to spread, it spreads quickly in only around 4% of patients. If you detect and remove an atypical nevus early, the prognosis is generally extremely good.

Remember that all atypical nevi should be observed and treated by a trained physician. This is the only way to determine whether the mole has become skin cancer. If you have noticed a new or changing growth on your body, schedule an appointment as soon as possible. The faster the treatment, the better the outlook.